Three-arm suspension for vehicles

ABSTRACT

A wheel suspension and transmission gear assembly may include: a main arm pivotally connectable at a connection point of the main arm to a shaft point of a wheel; a first linkage unit pivotally connected at its first end to the main arm; and a second linkage unit pivotally connected at its first end to the main arm such that at least a portion of the main arm is between the first linkage unit and the second linkage unit and such that a second end of the first linkage unit and a second end of the second linkage unit are at opposing sides of the main arm with respect to each other; wherein (i) the main arm and (ii) the first linkage unit or the second linkage unit each may include: a first gear and a second gear pivotally connected thereto and interconnected to transmit rotational motion between each other.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 16/789,761 filed on Feb. 13, 2020, which in turn is acontinuation application of U.S. patent application Ser. No. 16/268,616filed on Feb. 6, 2019 and granted as U.S. Pat. No. 10,723,191 on Jul.28, 2020, which claims the benefit of U.S. Provisional PatentApplication No. 62/692,787 filed on Jul. 1, 2018, all of which areincorporated herein by reference in their entirety. This application isalso a continuation in part of U.S. patent application Ser. No.16/854,921 filed on Apr. 22, 2020, which is a continuation of U.S.patent application Ser. No. 16/265,166 filed on Feb. 1, 2019 and grantedas U.S. Pat. No. 10,801,583 on Oct. 13, 2020, which claims the benefitof U.S. Provisional Patent Application No. 62/692,788 filed on Jul. 1,2018, all of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD OF THE INVENTION

The invention generally relates to suspension systems for vehicles, andmore particularly to suspension and transmission systems for vehicles.

BACKGROUND OF THE INVENTION

Suspension systems are the systems configured to suspend a vehiclechassis above its wheels, to maintain good grip on the road whileisolating the vehicle systems from road shocks and impacts. These can becontradicting demands that require compromising. Commonly usedsuspension systems, either rear or front, include: springs, shockabsorbers and the linkages between to the vehicle's chassis and thewheels, all of which are external to the wheels.

In-wheel suspension systems have several advantages as well aschallenges that must be overcome. Such suspension systems can reduce theweight of the vehicle and allow flexible damping of each wheelseparately. There are several examples of in-wheel suspension systemswhich require complicated connections to the vehicles' chassis or theuse of an expensive electrical suspension system in connection to anelectrical motor. Such systems cannot be implemented to every vehicle.

Mechanical gears for transferring rotational power between an inputshaft and one or more output shafts are usually used for one or more ofthe following purposes: setting a desired transfer ratio, changing therelative orientation, location and direction of the shaft between thespatial orientation of the input and the output axes (e.g., a 90-degreeshelical gear), and/or providing power transmission having one directionof power transmission (e.g., 90 degrees helical gears). In all of theseapplications, the distance and orientation between the input shaft andthe output shaft are fixed. There is need for gears that enabletransferring power from an input shaft to an output shaft in a desiredtransfer ratio, in an efficient and immediate manner.

SUMMARY OF THE INVENTION

Some aspects of the invention are directed to an in-wheel suspensionsystem that includes: an assembly that may include: a main arm pivotallyconnectable at a connection point (e.g., a midpoint) on the main arm toa shaft point of a wheel (e.g., included in: a hub-shaft of the wheel, abearing of the wheel, an axle of the wheel, etc.), at least a firstlinkage unit pivotally connected at a first end to a first end of themain arm, and at least a second linkage unit pivotally connected at afirst end to a second end of the main arm, wherein at least one secondend of the first linkage unit and at least one second end of the secondlinkage unit, that are not connected to the main arm, may be pivotallyconnectable each to a reference frame at a defined distance betweenthem, such as to form a substantially “Z” like shape.

In some embodiments, the assembly further includes at least a thirdlinkage unit having a first end pivotally connected to the main arm at adefined location and a second end pivotally connected to the referenceframe.

In some embodiments, least one of the first end and the second end ofthe third linkage unit may be pivotally connected via a spherical joint.

In some embodiments, least one of a first end of the first linkage unitpivotally connected at the first end of the main arm and a first end ofthe second linkage unit pivotally connected at the second end of themain arm are pivotally connected via a spherical joint.

In some embodiments, the at least one second end of the first linkageunit and at least one second end of the second linkage unit areconnected so as to allow the respective unit to pivot axially around afirst axis and a second axis respectively.

In some embodiments, the first axis and the second axis may be offparallel from each other.

In some embodiments, each linkage unit includes one or more linkingelements and two or more pivoting connections.

In some embodiments, the one or more linking elements may be selectedfrom the group consisting of: an arm, a rod, a lever and a shaft.

In some embodiments, the two or more pivoting connections are selectedfrom the group consisting of: bearings, hinges and spherical joints.

In some embodiments, the assembly may be configured to restrict themovement of the connection point with respect to the second ends of thefirst and the second linkage units along a substantially straight line.

In some embodiments, the overall width of the assembly exceeds the depthof the inner rim of the wheel.

In some embodiments, overall width of the assembly may be at most thedepth of the inner rim of the wheel.

In some embodiments, the suspension system further includes: a shockabsorbing unit. In some embodiments, the shock absorbing unit may beconnected to the assembly between two connection points configured toallow the shock absorbing unit to alter its length in response to changein the position of at least one of: the main arm and the first andsecond linkage units. In some embodiments, a rotary shock absorbing unitmay be connected to one of the pivoted connections of at least one of:the main arms and the first and second linkage units. In someembodiments, the shock absorbing unit may be connected between one of:the first end of the main arm and the at least one second end of thesecond linkage unit.

In some embodiments, the shock absorbing unit may be selected from thegroup consisting of: a spring, mono-tube shock absorber, twin-tube shockabsorber, Coilover shock absorber, a rotary damper, air shocks absorber,magnetic shocks absorber, energy harvesting shocks absorber andhydro-pneumatic shocks absorber.

In some embodiments, the reference frame may be one of: a chassis of thevehicle an element connectable to the chassis of the vehicle, an elementconnected to a conveyor, an element connected to a landing gear of anairplane and the like.

In some embodiments, the maximal allowable movement of the at least onesecond end of the first linkage unit or the at least one second end ofthe second linkage unit with respect to the connection point of the mainarm may be less than a radius of an inner rim of the wheel.

In some embodiments, a wheel may be presented, including an inner rimand the in-wheel suspension system according to description above,assembled in the inner rim.

In some embodiments, a method of assembling the in-wheel suspensionsystem according to description above in a vehicle is disclosed,including providing at least one in-wheel suspension assembly and ashock absorbing unit. In some embodiments, the shock absorbing unit maybe connected to the assembly between two connection points configured toallow the shock absorbing unit to alter its length in response to changein the position of at least one of: the main arm and the first andsecond linkage units. In some embodiments, the shock absorbing unit maybe connected to one of: the pivoted connections of the main arms and thefirst and second linkage units. In some embodiments, the method mayfurther include placing the in-wheel suspension system inside an innerrim of the wheel, pivotally connecting a connection point (e.g., at themidpoint) of the main arm to a shaft point of the wheel (e.g., a pointon the axis of: a hub shaft, a bearing, an shaft of the wheel, etc.),and pivotally connecting at least one second end of the at least onefirst linkage unit and at least one second end of the second linkageunit at a defined distance between them to a reference frame, such as toform a substantially “Z” like shape.

In some embodiments, the reference frame may be one of: a chassis of thevehicle and an element connectable to the chassis of the vehicle.

In some embodiments, the shock absorbing unit may be selected from thegroup consisting of: a spring, mono-tube shock absorber, twin-tube shockabsorber, Coilover shock absorber, a rotary damper, air shocks absorber,magnetic shocks absorber, energy harvesting shocks absorber andhydro-pneumatic shocks absorber.

In some embodiments, the connection point with respect to the secondends of the first and the second linkage units may be restricted to movealong a single substantially straight line.

In some embodiments, the maximal allowable movement of the at least onesecond end of the at least one first linkage unit or the at least onesecond end of the at least one second linkage with respect to theconnection point of the main arm may be less than a radius of the innerrim of the wheel.

Some embodiments of the present invention may provide a wheel suspensionand transmission gear assembly that may include: a main arm pivotallyconnectable at a connection point of the main arm to a shaft point of awheel; a first linkage unit pivotally connected at its first end to themain arm; and a second linkage unit pivotally connected at its first endto the main arm such that at least a portion of the main arm is betweenthe first linkage unit and the second linkage unit and such that asecond end of the first linkage unit and a second end of the secondlinkage unit are at opposing sides of the main arm with respect to eachother; wherein (i) the main arm and (ii) the first linkage unit or thesecond linkage unit each includes: a first gear and a second gearpivotally connected thereto and interconnected to transmit rotationalmotion between each other.

In some embodiments: the first gear of the first linkage unit or thesecond linkage unit is couplable to an input shaft being powered by arotational power source, the first gear of the main arm is rotatable bythe second gear of the first linkage unit or the second linkage unit,and the second gear of the main arm is couplable to an output shaftbeing coupled to the shaft point of the wheel.

In some embodiments, wherein the second gear of the first linkage unitor the second linkage unit and the first gear of the main arm rotatetogether about a common axis.

In some embodiments, wherein the gears of the main arm rotate in oneplane, and the gears of the first linkage unit or the second linkageunit rotate in a different plane that is substantially parallel to theplane in which the gears of the main arm rotate.

In some embodiments, the first gear and the second gear of at least oneof (i) the main arm and (ii) the first linkage unit or the secondlinkage unit, rotate in the same direction.

In some embodiments, at least one of (i) the main arm and (ii) the firstlinkage unit or the second linkage unit includes a drive belt or a drivechain interconnecting the respective first gear and the second gear.

In some embodiments, at least one of (i) the main arm and (ii) the firstlinkage unit or the second linkage unit includes an odd number of meshedgears to transmit rotation of the respective first gear to therespective second gear.

In some embodiments, the assembly further includes a shock absorbingunit.

In some embodiments, the shock absorbing unit is connected to at leastone of the first linkage unit and the second linkage unit to cause theshock absorbing unit to alter its length in response to a change in aposition of at least one of: the main arm, the first linkage unit andthe second linkage unit.

In some embodiments, the connection point of the main arm to the shaftpoint moves along a straight line in response to a change in a positionof at least one of: the main arm, the first linkage unit and the secondlinkage unit.

Some embodiments of the present invention may provide a wheel cornermodule that may include: a wheel suspension and transmission gearassembly, including: a main arm pivotally connectable at a connectionpoint of the main arm to a shaft point of a wheel; a first linkage unitpivotally connected at its first end to the main arm; and a secondlinkage unit pivotally connected at its first end to the main arm suchthat at least a portion of the main arm is between the first linkageunit and the second linkage unit and such that a second end of the firstlinkage unit and a second end of the second linkage unit are at opposingsides of the main arm with respect to each other; wherein (i) the mainarm and (ii) the first linkage unit or the second linkage unit eachincludes: a first gear and a second gear pivotally connected thereto andinterconnected to transmit rotational motion between each other; and adrivetrain unit include: an input shaft coupled to the first gear of thefirst linkage unit or the second linkage unit; an output shaft coupledto the second gear of the main arm and couplable to the shaft point ofthe wheel; and a rotational power source coupled to the input shaft.

In some embodiments, the first gear of the main arm is rotatable by thesecond gear of the first linkage unit or the second linkage unit.

In some embodiments, the second gear of the first linkage unit or thesecond linkage unit and the first gear of the main arm rotate togetherabout a common axis.

In some embodiments, the gears of the main arm rotate in one plane, andthe gears of the first linkage unit or the second linkage unit rotate ina different plane that is substantially parallel to the plane in whichthe gears of the main arm rotate.

In some embodiments, the first gear and the second gear of at least oneof (i) the main arm and (ii) the first linkage unit or the secondlinkage unit, rotate in the same direction.

In some embodiments, at least one of (i) the main arm and (ii) the firstlinkage unit or the second linkage unit includes a drive belt or a drivechain interconnecting the respective first gear and the second gear.

In some embodiments, at least one of (i) the main arm and (ii) the firstlinkage unit or the second linkage unit includes an odd number of meshedgears to transmit rotation of the respective first gear to therespective second gear.

In some embodiments, the wheel corner module includes a shock absorbingunit.

In some embodiments, the shock absorbing unit is connected to at leastone of the first linkage unit and the second linkage unit to cause theshock absorbing unit to alter its length in response to a change in aposition of at least one of: the main arm, the first linkage unit andthe second linkage unit.

In some embodiments, the connection point of the main arm to the shaftpoint moves along a straight line in response to a change in a positionof at least one of: the main arm, the first linkage unit and the secondlinkage unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with objects, features, and advantages thereof, may best beunderstood by reference to the following detailed description when readwith the accompanying drawings in which:

FIG. 1A is a schematic illustration of an in-wheel suspension systemassembled in a wheel traveling on a road according to some embodimentsof the invention;

FIG. 1B is a schematic illustration an in-wheel suspension systemassembled in a wheel at various poisons on the road according to someembodiments of the invention;

FIGS. 2A-2D are illustrations of in-wheel suspension assembliesaccording to some embodiments of the invention;

FIGS. 3A and 3B are illustrations of a wheel that includes in-wheelsuspension system according to some embodiments of the invention;

FIG. 4A is an illustration of an in-wheel suspension assembly accordingto some embodiments of the invention;

FIG. 4B is illustration of the in-wheel suspension system assembledinside an inner rim of a wheel and connected to a reference frame,according to some embodiments of the invention;

FIGS. 5A-5C are illustrations of the position of the arms of thein-wheel suspension system at 3 different positions of the wheel and thereference frame, according to some embodiments of the invention;

FIG. 6 is an illustration of an assembly of the in-wheel suspensionsystem in a conveyor according to some embodiments of the invention;

FIG. 7A is an illustration of an assembly of the in-wheel suspensionsystem in an airplane's landing gear according to some embodiments ofthe invention;

FIG. 7B is an illustration of commonly used airplane's landing gear forcomparison with the airplane landing gear of FIG. 7A;

FIG. 8 is a flowchart of a method of assembling an in-wheel suspensionsystem in a vehicle or a mechanical system according to some embodimentsof the invention;

FIGS. 9A and 9B are schematic illustrations of multi-link articulatedgearbox (MLAG) with two articulated links (L-MLAGs), according to someembodiments of the present invention;

FIGS. 10A and 10B schematically show a side view and an isometric view,respectively, of a multi-link articulated gearbox (MLAG), according tosome embodiments of the present invention;

FIG. 11 is a schematic illustration of a multi-link articulated gearbox(MLAG) including chain gears and drive chains, according to someembodiments of the present invention;

FIG. 12 is a schematic illustration of a multi-link articulated gearbox(MLAG) including belt gears and drive belts, according to someembodiments of the present invention;

FIG. 13 depicts exemplary use of a multi-link articulated gearbox (MLAG)of FIGS. 9A and 9B, according to an embodiment of the present invention;

FIGS. 14A and 14B are schematic illustrations of an in-wheel multi-linktransmission units (MLTU), according to some embodiments of the presentinvention;

FIG. 15A is a schematic illustration of a Multi-gear-wheel transmission(MGWT), according to some embodiments of the present invention;

FIG. 15B is a schematic isometric view of a MGWT, according to someembodiments of the present invention;

FIG. 15C is a schematic illustration of a two-links multi-gear-wheeltransmission (MGWT), according to some embodiments of the invention;

FIGS. 16A and 16B are schematic 3D diagrams of a wheel suspension andtransmission gear assembly, according to some embodiments of theinvention;

FIG. 16C is a schematic 3D diagrams of a wheel suspension andtransmission gear assembly and a wheel assembled to wheel suspension andtransmission gear assembly, according to some embodiments of theinvention;

FIG. 16D is a schematic illustration and FIG. 16E is a schematic 3Ddiagram of a wheel suspension and transmission gear assembly and a wheelassembled to the wheel suspension and transmission gear assembly,according to some embodiments of the invention; and

FIG. 17 is a schematic 3D diagram of a wheel corner module, according tosome embodiments of the invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.For example, the dimensions of some of the elements may be exaggeratedrelative to other elements for clarity. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components have notbeen described in detail so as not to obscure the present invention.

Some embodiments of the present invention may provide an in-wheelsuspension system that may include three arms in a Watt's linkageconfiguration all been assembled inside an inner rim of a wheel. Such asuspension system may be compact, light-weight and may further allow thedamping of each wheel separately, such that a bump or pothole in a roadunder one wheel may not affect at all any one of the other suspensionsystems of the other wheels. The in-wheel suspension system according tosome embodiments of the invention may further include a shock absorbingunit for damping and absorbing shocks from the bumps or potholes in theroad.

To better illustrate the general concepts of the invention, reference isnow made to FIG. 1A, which is a schematic illustration of an in-wheelsuspension system assembled in a wheel, for example, a wheel travelingon a road according to some embodiments of the invention. An in-wheelsuspension system 100 may be assembled so it may be accommodated atleast partially within a wheel 10 and may be connected to a referenceframe 8 of the vehicle (e.g., the chassis) indicated as dashed lines.In-wheel suspension system 100 may include a suspension assembly 105 anda shock absorbing unit 140. Suspension assembly 105 may have, whenassembled in wheel 10 and connected to a reference frame (e.g., thevehicle chassis), substantially a ‘Z’ like shape (as illustrated). Thesubstantially a ‘Z’ like shape may relate to a straight ‘Z’ like shapeand to a mirror image of a ‘Z’ like shape. The ‘Z’ like shape may bedefined at a single plane (i.e., movements of its two parallel or nearto parallel parts are in the same plane) or may have three-dimensionalconfiguration (i.e., its two parallel or near to parallel parts mayoperate out of a common plane). Accordingly, any shape that includes amain arm connected at each of its ends to an additional arm (or units)such that the other ends of the two arms are pointing at substantiallyopposite directions—are in the scope of the invention.

The ‘Z’ like shape of assembly 105 may allow connection point 115 (e.g.,the midpoint) to connect assembly 105 to a shaft point 18 of wheel 10and to move in a substantially straight line, permitting uprightmovement in the direction of the Z axis in the drawing when wheel 10 ison road 50. In some embodiments, shaft point 18 of wheel 10 may be theaxis of at least one of: hub shaft, a bearing, a shaft of the wheel 10,etc. The Z direction is defined by a line passing through point 55 atwhich wheel 10 touches road 50 and through connection point 115.Directions X and Y are orthogonal to direction Z, wherein direction X isthe direction of the rolling of wheel 10. In some embodiments,connection point 115 may be located at the midpoint, thus substantiallythe same distance from road 50 regardless of the conditions, such asbumps or potholes in road 50, as illustrated in FIG. 1B, the ‘Z’ likeshape of assembly 105 may allow connection point 115 to move, withrespect to all the other elements of system 100, in a substantiallystraight line along the Z axis direction or any other direction. Thus,in some embodiments, when a chassis of the vehicle is connected toassembly 105 the chassis (and other system of the vehicle) may beallowed to move with respect to road 50, as will be illustrated anddiscussed in detail in FIGS. 5A-5B.

Reference is now made to FIGS. 2A-2D which are illustrations of in-wheelsuspension assemblies according to some embodiments of the invention. Asuspension assembly 105 may include a main arm 110 (also known in theart as an upright) pivotally connectable at a connecting point 115, 115′or 155″ of main arm 110 to a shaft point 18 of wheel 10, which may be onthe axis of a hub shaft 18, a wheel axle 18, or a bearing 18 of a wheel10 (illustrated in details in FIGS. 3A-3B). As used herein, the term“pivotally connected” may refer to any pivoting connection, either astraight pivot (e.g., a bearing) or a spherical joint. Suspensionassembly 105 may further include at least a first linkage unit 120pivotally connected at a first end 122 to a first end of main arm 110and at least a second linkage unit 130 pivotally connected at a firstend 132 to a second end of main arm 110.

In some embodiments, the connection point may be positioned at themidpoint 115 of main arm 110. Connection point 115 may be located ateven distances from the connections at first end 122 and first end 134.In some embodiments, other locations may be considered for theconnection point, for example, asymmetrical connection points 115′ and115″ located at different distances from first end 122 and first end134. For example, an asymmetrical arrangement may allow suspensionsystem 100 and a shock absorbing unit (e.g., shock absorbing unit 140illustrated in FIGS. 3A-4B) to encounter a bump (e.g., when the wheeltravels upwards relative to the chassis) while experiencing greaterforces than when encountering a pothole. In some embodiments, anasymmetrical arrangement may include, different lengths for firstlinkage unit 120 and second linkage unit 130.

As should be understood by one skilled in the art, the connection point115 illustrated at even distances from the connections at first end 122and first end 134, in FIGS. 2-5, is given as an example only. In someembodiments, asymmetrical locations 115′ and 115″ may be considered asoptional replacements to connection point 115.

In some embodiments, at least one second end 124 of first linkage unit120 and at least one second end 134 of second linkage unit 130 that arenot connected to main arm 110 may be pivotally connected each to areference frame 8 (illustrated in FIG. 3B) at a defined distance betweenthem, such as to form a substantially “Z” like shape. The substantially“Z” like shape may allow main arm 110 and at one first linkage unit 120and at least one second linkage unit 130 to form and act as a Watt'slinkage configuration.

As used herein, a substantially “Z” like shape may not necessarily be ona single plane but may have slightly three-dimensional movement, as longas the principle of the Watt's linkage configuration may be sustained.Therefore, in some embodiments, assembly 105 may be configured torestrict the movement of connection point 115 with respect to secondends 124 and 134 of the first and the second linkage units 120 and 130along a substantially straight line.

In some embodiments, assembly 105 may further include at least a thirdlinkage unit 160, illustrated in FIGS. 2C and 2D. Third linkage unit 160may have a first end 162 pivotally connected to main arm 110 at adefined location and a second end 164 pivotally connected to referenceframe 8 (illustrated in FIG. 3B). In some embodiments, at least one offirst end 162 and second end 164 of third linkage unit 160 may bepivotally connected via a spherical joint, as illustrated.

In some embodiments, each linkage unit 120, 130 or 160 may include oneor more linking elements and two or more pivoting connections. A linkingelement according to embodiments of the invention may include anystructural element that can be pivotally connected to main arm 110 andto reference frame 8 (illustrated in FIG. 4B). For example, linkingelement may include one or more arms, one or more rods, a lever, a shaftand/or a profile as illustrated in FIGS. 2A-2D. For example, firstlinkage unit 120, illustrated in FIG. 2A, may include two linkingelements 121 and 122 (e.g., arms or rods), each being pivotallyconnected to main arm 110 at two first ends 122, and may further beconnected to reference frame 8 at additional two second ends 124.

In another example, illustrated in FIG. 2B, first linkage unit 120 mayinclude a single ‘H’ like linkage element 125 connected to main arm 110at two first ends 122 and connected to reference frame 8 (illustrated inFIG. 4B) at additional two second ends 124. In some embodiments, ‘H’like linkage element 125 may be pivotally connected to the main armand/or farm 8 via two axles. In some embodiments, linkage element 125may not include an ‘H’ like shape and may be defined merely by beingconnected via a single axle at each of its ends, a first axle in end 122and a second axle in end 124. In some embodiments, the ‘H’ like linkageelement 125 may be made from ridged profiles (as illustrated) or mayinclude any other elements either rigidly or pivotally connected.

In yet another example illustrated in FIG. 2C, first linkage unit 120may include a single ‘V’ like linkage element 126 connected to main arm110 a single first ends 122 and may be connected to reference frame 8 atadditional two second ends 124. In some embodiments, ‘V’ like linkageelement 126 may be pivotally connected via a spherical joint at one end(e.g., end 122) and via one axle at the other end (e.g., end 124). Insome embodiments, linkage element 126 may not include a ‘V’ like shapeand may further be defined only by the two different pivot connectionsat its two ends.

In a forth example illustrated in FIG. 2D first linkage unit 120 mayinclude two linkage elements 128 and 129 each being a rod pivotallyconnected (e.g., via a spherical joint) at a first end 122 to main arm110 and at two second ends 124 to a reference frame (e.g., frame 8illustrated in FIG. 4B). Linkage unit 130 of FIG. 2D may include twolinkage elements 138 and 139, each being a rod pivotally connected(e.g., via a spherical joint) at a first end 132 to main arm 110 and attwo second ends 134 to a reference frame (e.g., farm 8 illustrated inFIG. 4B), and linkage unit 160 may include a single linkage elements 161pivotally connected (e.g., via a spherical joint) to main arm 110 at afirst end 162 and to the reference frame at second end 164.

In yet additional example, second linkage unit 130 may include a ‘V’shaped linkage element 131 illustrated in FIGS. 2A-2C and configured tobe connected to main arm 110 at single first ends 132 and may beconnected to reference frame 8 (illustrated in FIG. 4B) at additionaltwo second ends 134. In another example illustrated in FIG. 2D, secondlinkage unit 130 may include two linkage elements 138 and 139 each beinga rod pivotally connected (e.g., via a spherical joint) at a first end132 to main arm 110 and at two second ends 134 to a reference frame. Inthe embodiment illustrated in FIG. 2C, third linkage unit 160 mayinclude a single linkage element 161 pivotally connected (e.g., via aspherical joint) to main arm 110 at a first end 162 and to the referenceframe at second end 164. Additional examples of linkage units andlinkage elements are given in FIGS. 3-4.

In some embodiments, pivoting connections to be include in linkageunits, 120, 130 and/or 160 may include any connection that may allowpivoting around at least one axis. For example, the pivoting connectionsmay include: bearings, bushings, hinges, spherical joints (e.g., balljoints, Heim joints, etc.) and the like. For example, at least one offirst end 122 of first linkage unit 120 may be pivotally connected atthe first end of main arm 110 via a spherical joint, as illustrated inFIGS. 2C and 2D. In some embodiments, first end 132 of second linkageunit 130 may be pivotally connected at second end of the main arm 110via a spherical joint, as illustrated in FIGS. 2A-2D. In someembodiments, first end 122 of first linkage unit 120 and/or first end132 of second linkage unit 130 may be connected via bearing, asillustrated in FIGS. 3-5.

In some embodiments, at least one second end 124 of first linkage unit120 and at least one second end 134 of second linkage unit 130 may beconnected so as to allow the respective unit to pivot axially around afirst axis 12 and around a second axis 13 respectively, as illustratedin FIGS. 2A-2C and FIGS. 3-5. Such a connection may require the use ofone or more bearing. In some embodiments, first axis 12 and second axis13 may be off parallel from each other, as to allow a slight camber ofwheel 10.

Reference is now made to FIGS. 3A-3B which are illustrations of anin-wheel suspension system assembled inside a vehicle's wheel accordingto some embodiments of the invention. An in-wheel suspension 100 may beassembled in a wheel 10 of a motorized vehicle or in a wheel 10 of anon-motorized vehicle. In-wheel suspension 100 may include an assembly205 and a shock absorbing unit 140. Wheel 10 may include a tire 20, aninner rim 16 and a shaft point 18.

Assembly 105, illustrated in greater details in FIG. 4A, may include amain arm 110 (also known in the art as up-right arm) pivotallyconnectable at a connection point 115 of main arm 110 to shaft point 18of wheel 10 (e.g., located on the axis of one of: a hub shaft, a bearingof wheel 10, an axle of the wheel 10, etc.), a first linkage unit 220pivotally connected at a first end 222 to a first end of main arm 110and a second linkage unit 230 pivotally connected at a first end 232 toa second end of main arm 110. In some embodiments, a second end 224 offirst linkage unit 220 and a second end 234 of second linkage unit 230,not connected to main arm 110, may be pivotally connected to a referenceframe, for example, a reference frame 8 (e.g., a chassis) illustrated inFIG. 4B. In some embodiments, second end 224 and second end 234 may bepivotally connected at a defined distance between them, such as to forma 7′ like shape typical to the Watt's linkage configuration.

In some embodiments, connection point 115 of main arm 110 may berestricted to move with respect to second ends 224 of first linkage unit120 and 234 of second linkage unit 130 along a single substantiallystraight line, as illustrated and discussed with respect to FIGS. 5A-5C.In some embodiments, at connection point 115, main arm 110 may includeany designated bore for holding a bearing configured to bear the hubshaft of wheel 10. In some embodiments, at end 222 and 232, main arm 110may include designated bores for holding bearings configured to bearpivots as to allow main arm 110 to be pivotally connected to first andthe second linkage units 220 and 230. In some embodiments, thedesignated bores may each be configured to hold a first part of aspherical joint, which may allow the connections between main arm 110and linkage units 220 and 230 to be pivoted around more than one axis,as disclosed and discussed above with respect to FIGS. 2A-2D.

Main arm 110 may have a profile and dimensions sufficient to sustainforces and stresses applied on main arm 110 from one of: the hub shaft,and/or bearings of wheel 10 and linkage units 220 and 230. Main arm 110may further be loaded by a shock absorbing unit 140. Main arm 110 may bemade from any suitable material, for example, various types of steel,and/or composite materials. For example, a main arm 110 for a passengercar weighing 1600 Kg having rim diameter of 17″ may be configured tohold loads of 800 Kg. Such an arm 110 may have a 20 mm thinness profile.

First linkage unit 220 may include a first bore at end 222 for holding abearing to allow a pivot to pivotally connect first linkage unit 220 tomain arm 110. In some embodiments, the bore may hold a second part of aspherical joint to allow linkage unit 220 and main arm 110 to be pivotedaround more than one axles. First linkage unit 220 may further include asecond bore at end 224 for holding a bearing as to allow a pivot topivotally connect first linkage unit 220 to reference frame 8(illustrated in FIG. 4B) and shock absorbing unit 140.

First linkage unit 220 may include a single linkage element having aprofile and dimensions sufficient to endure loads and forces applied bymain arm 110 shock absorbing unit 140 and the chassis of the vehicle(illustrated in FIG. 4B).

Second linkage unit 230 may include a first bore at end 232 for holdinga bearing to allow a pivot to pivotally connect second linkage unit 230to main arm 110. In some embodiments, the bore may hold a second part ofa spherical joint to allow linkage unit 230 and main arm 110 to bepivoted around more than one axle. First linkage unit 220 may furtherinclude a second bore at end 234 for holding a bearing to allow a pivotto pivotally connect second linkage unit 230 to reference frame 8(illustrated in FIG. 4B).

Second linkage unit 230 may have a profile and dimensions sufficient toendure loads and forces applied by main arm 110 and chassis of thevehicle (illustrated in FIG. 4B).

In some embodiments, shock absorbing unit 140 may be any unit that canbe assembled into assembly 105 that is configured to absorb, damp,reduce, etc., shocks applied to assembly 105 by external forces. Shockabsorbing unit 140 may be a compacted unit that may allow the assemblyof suspension system 100 in rim 16. In some embodiments, the shockabsorbing unit may be connected to the assembly between two connectionpoints configured to allow the shock absorbing unit to alter its lengthin response to a change in the position of at least one of: the main armand the first and second linkage units. For example, such a leaner shockabsorbing unit 140 may be connected at one end to one of: first linkageunit 120 and second linkage unit 130 and at the other end to bepivotally connected to the reference farm (e.g., farm 8 illustrated inFIG. 4B).

In some embodiments, shock absorbing unit 140 may be a rotary shockabsorbing unit configured to rotate as a function of the wheel movement.In some embodiments, a rotary shock absorbing unit 140 may be connectedto one of the pivoting connections of the main arms and the first andsecond linkage units, for examples, in ends 122/222, 124/224, 132/232and/or 134/234. For example, shock absorbing unit 140 may be a rotaryspring or a rotary damper.

Shock absorbing unit 140 may include any mechanical, hydraulic,magnetic, electrical, pneumatic devices or combination thereof that maybe configured to absorb and dampen shock impulses, by converting thekinetic energy of the shock into heat, electrical current and/ormagnetic flux. Shock absorbing unit 140 may include at least one of: aspring (illustrated in FIG. 1A), mono-tube shock absorber, twin-tubeshock absorber, Coilover shock absorber (illustrated in FIG. 1B), arotary damper, air shocks absorber, magnetic shocks absorber, energyharvesting shocks absorber and hydro-pneumatic shocks absorber and thelike.

In some embodiments, assembly 205 may further include arm extension 250,illustrated in FIG. 4A, for extending the distance between end points224 and 232 to increase the stroke of shock absorbing unit 140. In someembodiments, assembly 105 may further include one or more limits 260,also illustrated in FIG. 2A, for preventing end 132 from hitting end 224and/or preventing end 222 from hitting end 234.

Reference is now made to FIG. 4B, which is an illustration of in-wheelsuspension 100 assembled inside a rim 16 of wheel 10 and connected toreference frame 8, for example, connected to a chassis of a vehicle,according to some embodiments of the invention. In some embodiments, themaximal allowable movement of second end 124 or 224 of first linkageunit 120 or 220 or second end 134 or 234 of second linkage unit 130 or230 with respect to connection point 115 of main arm 110 may be lessthan an inner radius of inner rim 16 of wheel 10. Such configuration mayallow inner rim 16 to fully accommodate assembly 105 or 205 of in-wheelsuspension 100. In some embodiments, the width of assembly 105 or 205may be less than the depth of the inner rim of the wheel. In someembodiments, the overall width of assembly 105 or 205 may exceed thedepth of inner rim 16 of wheel 10 as illustrated in FIG. 1B. In someembodiments, most of the width of assembly 105 or 205 may beaccommodated inside inner space of rim 16 of wheel 10, as illustrated inFIG. 1A and FIGS. 3A-3B.

Reference is now made to FIGS. 5A-5C which are illustrations of theposition of the arms of the in-wheel suspension at 3 different positionsof the wheel and the chassis, according to some embodiments of theinvention. The two dashed line presents the position of the vehicle'schassis when the vehicle is on a road 50. A discussed herein above, suchan assembly may allow connection point 115 connected to shaft point 18of the wheel 10, to move in substantially straight line and to form theWatt's linkage. Therefore, when wheel 10 hits road 50, regardless of theconditions of the road, the chassis (presented in dashed lines) is keptsubstantially at the same place and only linkage units 120/220 and130/230 and shock absorbing unit 140 are configured to move. Forexample, when the wheel hits a bump 52 in road 50, as illustrated inFIG. 5A, end point 124/224 of linkage unit 120/220 apply force on shockabsorbing unit 140, causing unit 140 to compress and absorb the impactfrom bump 52 and further allow connection point 115 (e.g., the midpoint)to move upwards while allowing the chassis to stay at substantially thesame location with respect to road 50. In another examples, illustratedin FIG. 3B, assembly 105/205 is completely balanced on road 50 such thatconnection point 115 is located at the a-point determined by preloadsetting between end 124/224 and end 134/234 when the wheel is travelingon a flat road 50. However, when the wheel hits a pit 54 in road 50,illustrated in FIG. 5C, ends 124/224 and 134/234 are pushed upwards,shock absorbing unit 140 extends (e.g., while absorbing the shock)allowing connection point 115 to move downwards while allowing thechassis to stay at substantially the same location with respect to road50.

As can be seen from FIGS. 5A-5C an in-wheel suspension system accordingembodiments of the invention may allow a vehicle to remain substantiallybalanced on the road regardless of the obstacle each wheel tacklesseparately, thus allowing much more comfortable ride to passengers inthe vehicle.

As would be understood by one skilled in the art, the linkage units, thepivoting connections and the linkage elements illustrated and discussedwith respect to FIGS. 2-5 are given as examples only, and the inventionas a whole is not limited to these specific configurations.

Reference is now made to FIG. 6, which is an illustration of thein-wheel suspension system assembled in a conveyor according to someembodiments of the invention. A conveyor 600 may include a belt 605 andone or more wheels 610, each including in-wheel suspension system 100according to some embodiments of the invention. In some embodiments, theassembled in-wheel suspension system 100 may allow damping shocks causedby various goods uploaded to conveyor 600, thus protecting the motor(not illustrated) and other drivetrain and structural parts of conveyor600. In some embodiments, the uploaded goods may apply substantially anominal load (e.g., the average load to which the conveyor were designedto carry) on conveyor 600. In such a case, suspension system 100 mayabsorb the load and may remain substantially at its nominal (e.g.,center) position. In some embodiments, when conveyor 600 is loaded withloads either higher or lower than the nominal load, the main arm andlinkage units of suspension system 100 may move to allow both shockabsorbing and a movement compensation. In case of a load higher than thenominal load, suspension system 100 may be compressed, and in case of aload lower than the nominal load, suspension system 100 may be extended.

Reference is now made to FIG. 7A, which is an illustration of anairplane landing gear according to some embodiments of the invention. Alanding gear 700 may include two or more wheels 710, each including anin-wheel suspension system 100 according to some embodiments of theinvention. In comparison, the commonly used landing gear illustrated inFIG. 7B includes two or more wheels 750 each being damped by an externalshock absorber 760. Therefore, the commonly used landing gear haslimited size for wheels 750, since room must be left for shock absorbers760. Furthermore, all of wheels 750 are assembled to a single rigidchassis, which forces all the wheels to act together in response anyobstacle.

In comparison, placing suspension system 100 inside wheel 710 may allowextending the diameter of wheels 710, thus allowing a better traction ofwheels 710. In some embodiments, placing suspension system 100 insidewheel 710 may allow saving of the total volume consumed by landing gear700. Furthermore, landing gear 700 may allow each one of wheels 710 totackle an obstacle separately, thus providing better sock absorbing tothe airplane.

In some embodiments, in-wheel suspension system 100 may be assembled inother mechanical or machinery systems, and reference frame 8 may beincluded in or connected to such mechanical or machinery systems. Insome embodiments, when a motorized industrial system includes a narrowfootprint of a rotating shaft which requires a predictable dynamicresponse, an in-wheel suspension 100 according to some embodiments ofthe invention may provide the necessary solution. For example,suspension 100 may be implemented to various textile machines,mechanical presses, industrial printers and the like. As should beunderstood by one skilled in the art, the vehicle, the conveyor and theairplane landing gear are given as examples only.

Reference is now made to FIG. 8, which is a flowchart of a method ofassembling an in-wheel suspension in a vehicle or other mechanicalsystem according to some embodiments of the invention. In box 410, atleast one in-wheel suspension systems may be provided, for example, oneof in-wheels suspension systems 100 illustrated in FIGS. 1-5. In someembodiments, a first pair of in-wheels suspension systems 100 may beprovided to be assembled to the front wheels of the vehicle, and/or asecond pair of in-wheels suspension systems 100 may be provided to beassembled to the rear wheels of the vehicle.

In box 420, the in-wheel suspension may be placed inside an inner rim ofthe wheel. For example, in-wheel suspension system 100 may be placedinside inner-rim 16, as illustrated in FIGS. 1A, 1B, 3A, 3B, 4A and5A-5C. In box 430, a connection point of the main arm may be pivotallyconnected to a shaft point of the wheel. For example, midpoint 115 mayinclude a bore and a bearing to be pivotally connected shaft point 18 ofwheel 10.

In box 440, a second end of the first linkage unit and the second end ofthe second linkage unit may be pivotally connected at a defined distancebetween them to a reference frame (e.g., reference frame 8) such as toform a substantially ‘Z’ like shape. For example, second end 124 offirst linkage unit 120 and second end 134 of second linkage unit 130 maybe connected at a predefined distance to reference frame 8, which maybe, for example, the chassis of the vehicle or an element connectable tothe chassis of the vehicle. In some embodiments, reference frame 8 maybe included in any mechanical system, such as conveyor 600 and landinggear 700 illustrated in FIGS. 6-7. Such a connection may form a Watt'slinkage that includes main arm 110, first linkage unit 120 and secondlinkage unit 130, as to allow the movement of connection point 115 to berestricted with respect to the second ends of the first and the secondlinkage units (e.g., ends 124 and 134) along a single substantiallystraight line (e.g., the normal to the road, when the vehicle is on theroad). In some embodiments, when assembled inside the inner rim, themaximal allowable movement of the second end of the first linkage unitor the second end of the second linkage unit with respect to theconnection point of the main arm may be less than a radius of the innerrim of the wheel.

Some embodiments of the present invention may provide a multi-linktransmission gear for transmitting rotational power from an input shaftto an output shaft. According to some embodiments of the invention, inorder to, for example, enable movement of an output shaft with respectto an input shaft, two or more links in a multi-link articulated gear(MLAG) may be pivotally connected to each other, each link may includeat least two gears interconnected with each other. It is noted that,throughout the description of embodiments of this invention, the term“link” or “link of MLAG” (hereinafter L-MLAG) can refer to a mechanicaljoint that fixedly connects two rotation axes to one another so that theaxes are parallel to each other and are distanced so that gears that arerotating about the axes may drive (i.e., rotate) each-other, for examplein the form of meshed gears, in the form of chain drive, in the form ofdrive belt, hydraulic, magnetic, and/or other power transferencemechanisms as are known in the art. At least one axis of the link(L-MLAG) may serve also as a pivot enabling one L-MLAG to rotate (orswivel) about the at least one axis, thereby changing a relative anglebetween the lines in each L-MLAG that connect two adjacent axes. In someembodiments, two neighbor L-MLAGs re pivoted as described above so that,the gears of one L-MLAG are disposed in a plane different from that ofthe neighbor L-MLAG. In some embodiments described hereinbelow, rotationmovement originating by a gear in one L-MLAG is transferred to aneighbor gear in the neighbor L-MLAG, which then its rotation istransferred to the other gear in the same L-MLAG.

Each L-MLAG may include a supporting structure and two or more gears.The supporting structure may support, e.g., by means of pivots (or axes)each of the gears and/or allow them to freely rotate while geared witheach other. Each two neighboring L-MLAGs can share a common axis thatcan function both as rotation axis for a common gear and/or as an axisfor changing the relative angle between the two neighboring L-MLAGs.

Reference is made to FIGS. 9A and 9B, which are schematic illustrationsof multi-link articulated gearbox (MLAG) 900 with two articulated links(L-MLAGs), according to some embodiments of the present invention. FIG.9A shows a schematic side view of MLAG 900 and FIG. 9B shows a schematictop view of MLAG 900.

According to some embodiments of the invention, MLAG 900 includes afirst L-MLAG 902A and second L-MLAG 902B.

First L-MLAG 902A may include a first support 903A. First L-MLAG 902Amay include a first gear 904A, a second gear 904B. First gear 904A andsecond gear 904B of first L-MLAG 902A may be interconnected to transmitrotational motion between each other. In some embodiments, first L-MLAG902A includes a third gear 904C meshed with first gear 904A and secondgear 904B of first L-MLAG 902A (e.g., as shown in FIGS. 9A and 9B).

Second L-MLAG 902B may include a second support 903B. Second L-MLAG 902Bmay include a first gear 906A, a second gear 906B. First gear 906A andsecond gear 906B of second L-MLAG 902B may be interconnected to transmitrotational motion between each other. In some embodiments, second L-MLAG902A includes a third gear 906C meshed with first gear 906A and secondgear 906B of second L-MLAG 902B (e.g., as shown in FIGS. 9A and 9B).

In some embodiments, gears 904A-904C of first L-MLAG 902A rotate in oneplane (e.g., a plane 901A shown in FIG. 9B), and gears 906A-906C ofsecond L-MLAG 902B rotate in a different plane (e.g., a plane 901B shownin FIG. 9B) that is substantially parallel to the plane of first L-MLAG902A (e.g., as shown in FIG. 9B). In some embodiments, second gear 904Bof first L-MLAG 902A shares a common rotation axis 908 with first gear906A of second L-MLAG 902B. In some embodiments, second gear 904B offirst L-MLAG 902A and first gear 906A of second L-MLAG 902B rotatetogether. For example, MLAG 900 may include a shaft 909 that connectssecond gear 904B of first L-MLAG 902A and first gear 906A of secondL-MLAG 902B such that gears 904B, 906A, and shaft 909 may rotatetogether about rotation axis 908 (e.g., as shown in FIG. 9B).

In some embodiments, shared common rotation axis 908 is also the axis ofrotation of first L-MLAG 902A with respect to second L-MLAG 902B (e.g.,as shown in FIGS. 9A and 9B).

Since gears 904A-904C of first L-MLAG 902A and gears 906A-906C of secondL-MLAG 902B rotate together, when, for example, gear 904A is powered(turned or rotated) it causes gears 904B-904C of first L-MLAG 902A andgears 906A-906C of second L-MLAG 902B to rotate with it, each about itsrespective axis, while respective L-MLAGs 902A, 902B may remainstationary or move independently. Since first and second L-MLAGs 902A,902B are connected via a common axis 908, their relative angle 910 maybe changed by rotating either of the L-MLAGs 902A, 902B about axis 908.As shown in FIG. 9A, axis 908 may allow gears 904B, 906A to rotateindependently of the rotation of either L-MLAG 902A or 902B about axis908. Accordingly, rotational power may be provided to, for example,first gear 904A of first L-MLAG 902A (e.g., referred also as input gear904A) and may be continuously transferred to gear 906B of second L-MLAG902B (e.g., referred also as output gear 906B), and the relative anglebetween L-MLAG 902A and L-MLAG 902B may change independently of therotation of the gears. As a result, rotational power may be transferredfrom input gear 904A to output gear 904C while the distance betweentheir axes may be changed, by changing the relative angle betweenL-MLAGs 902A and 902B, independently of the rotation of the gears. Insome embodiments, the way one L-MLAG may be rotated about a common axiswith respect to a neighbor L-MLAG applies also to the way it may rotateabout an axis connected to a reference frame, with respect to thereference frame.

Reference is now made to FIGS. 10A and 10B, which schematically show aside view and an isometric view, respectively, of a multi-linkarticulated gearbox (MLAG) 1000, according to some embodiments of thepresent invention.

MLAG 1000 depicts two L-MLAGs 1002A, 1002B positioned in differentplanes that are parallel (or substantially parallel) to each other. WhenMLAG 1000 is connected at one end to a static point 1001, the other end1002 may move so as to change a distance D between end 1002 and point1001 as depicted by angular arrow 1003. In some embodiments, the outputgear of MLAG 1000 may be in a different plane than that of the inputgear of MLAG 1000.

Reference is now made to FIG. 11, which is a schematic illustration of amulti-link articulated gearbox (MLAG) 1100 including chain gears anddrive chains, according to some embodiments of the present invention.

According to some embodiments of the invention, MLAG 1100 includes afirst L-MLAG 1102A and second L-MLAG 1102B.

First L-MLAG 1102A may include a first support 1103A. First L-MLAG 1102Amay include a first chain gear 1104A (e.g., first chain wheel 1104A), asecond chain gear 1104B (e.g., a second chain wheel 1104B). First gear1104A and second gear 1104B of first L-MLAG 1102A may be interconnectedto transmit rotational motion between each other. In some embodiments,first L-MLAG 1102A includes a drive chain 1104C interconnecting firstgear 1104A and second gear 1104B of first L-MLAG 1102A (e.g., as shownin FIG. 11).

Second L-MLAG 1102B may include a second support 1103B. Second L-MLAG1102B may include a first chain gear 1106A (e.g., first chain wheel1106A), a second belt gear 1106B (e.g., second belt wheel 1106B). Firstgear 1106A and second gear 1106B of second L-MLAG 1102B may beinterconnected to transmit rotational motion between each other. In someembodiments, second L-MLAG 1102A includes a drive chain 1106Cinterconnecting first gear 1106A and second gear 1106B of second L-MLAG1102B (e.g., as shown in FIG. 11).

Reference is now made to FIG. 12, which is a schematic illustration of amulti-link articulated gearbox (MLAG) 1200 including belt gears anddrive belts, according to some embodiments of the present invention.

According to some embodiments of the invention, MLAG 1200 includes afirst L-MLAG 1202A and second L-MLAG 1202B.

First L-MLAG 1202A may include a first support 1203A. First L-MLAG 1202Amay include a first belt gear 1204A (e.g., first belt wheel 1204A), asecond belt gear 1204B (e.g., a second belt wheel 1204B). First gear1204A and second gear 1204B of first L-MLAG 1202A may be interconnectedto transmit rotational motion between each other. In some embodiments,first L-MLAG 1202A includes a drive belt 1204C interconnecting firstgear 1204A and second gear 1204B of first L-MLAG 1202A (e.g., as shownin FIG. 12).

Second L-MLAG 1202B may include a second support 1203B. Second L-MLAG1202B may include a first belt gear 1206A (e.g., first belt wheel1206A), a second belt gear 1206B (e.g., second belt wheel 1206B). Firstgear 1206A and second gear 1206B of second L-MLAG 1202B may beinterconnected to transmit rotational motion between each other. In someembodiments, second L-MLAG 1202A includes a drive belt 1206Cinterconnecting first gear 1206A and second gear 1206B of second L-MLAG1202B (e.g., as shown in FIG. 12).

It is noted that combinations of different L-MLAG configurations withinthe same MLAG are possible. For example, a first L-MLAG in a MLAG mayinclude meshed gears (e.g., as described above with respect to FIGS. 9Aand 9B), and a second L-MLAG in the MLAG may include chain gearsinterconnected by a drive chain (e.g., as described above with respectto FIG. 11). In another example, a first L-MLAG in a MLAG may includemeshed gears (e.g., as described above with respect to FIGS. 9A and 9B),and a second L-MLAG in the MLAG may include belt gears interconnected bya drive belt (e.g., as described above with respect to FIG. 12). Inanother example, a first L-MLAG in a MLAG may include meshed gears chaingears interconnected by a drive chain (e.g., as described above withrespect to FIG. 11), and a second L-MLAG in the MLAG may include beltgears interconnected by a drive belt (e.g., as described above withrespect to FIG. 12).

According to some embodiments of the invention that were describedabove, the following are features that may be realized using amulti-link articulated gearbox (MLAG) of the invention:

Allowing steep angle of motion between input and output, i.e., largemovement in one direction while keeping a slim or wide profile on otherdirections, to save volume occupied or bridge gaps, e.g., if the slimprofile allows large travel and free low-resistance movement along theplane perpendicular to rotating shafts while minimizing distance in thedirection of the shaft.

Enabling easy and simple integration of a clutch mechanism.

Enabling easy and simple integration of rotational speedreduction/increasing gear(s).

Supporting transfer of high torque, high rotational speeds and highpower, efficiently.

Providing simple and free-standing system that does not require controlor complicated subsystems (electronics, oil pump or other controlapparatus) enabling transference of the power in a reliable manner.

Supporting two-way (forward and backward) power transfer through thesystem.

In some embodiments, a transmission gear constructed and operatingaccording to the description above may be used, for example, forproviding simple and reliable driving system for wheels traveling alongbumpy road, by providing, by means of a multi-link articulated gearbox(MLAG) of the invention, rotational power to an input axis that isstatic with respect to the traveling vehicle and transferring therotational power to a wheel following the bumpy road (and thereforedynamic with respect to the travelling vehicle).

Reference is now made to FIG. 13, which depicts exemplary use of amulti-link articulated gearbox (MLAG) of FIGS. 9A and 9B, according toan embodiment of the present invention.

FIG. 13 depicts MLAG 1300 that is similar to MLAG 900 described abovewith respect to FIGS. 9A and 9B.

MLAG 1300 may be used to provide rotational power from a rotationalsource 1352 (e.g., a motor) via a first L-MLAG 1353A and a second L-MLAG1353B to a wheel 1354. The freedom of second L-MLAG 1353B to move asindicated by arrow 1356, while the rotational source 1352 is static withrespect to a reference frame (e.g., a vehicle's chassis), allows wheel1354 to move as indicated by arrow 1355, for example when followingbumps on a road.

Reference is now made to FIGS. 14A and 14B, which are schematicillustrations of an in-wheel multi-link transmission units (MLTU) 1403and 1460, respectively, according to some embodiments of the presentinvention.

MLTU 1403 in FIG. 14A may include two or more transmission links, thatcan transfer rotational power from a power input 1403A to a power output1403B. Power input 1403A may be a motor, a gear or the like. Poweroutput 1403B may be connected to a wheel and can drive (e.g., rotate)the wheel. MLTU 1403 may provide flexibility and freedom of movementbetween the power input 1403A and the wheel. In some embodiments, MLTU1403 may be included, partially or fully, within the wheel rim, therebyenabling efficient occupation of an installation space. FIG. 14Aillustrates wheel 1402 in two positions: a lower position 1400A on theleft side and at a higher position 1400B on the right side. The verticaldisplacement of wheel 1402, 1401B, exemplifies the vertical freedom ofmovement of wheel 1402, while power input 1403A remains at the samelevel 1401A. FIG. 14B depicts MLTU 1460, that similarly to MLTU 1403,provides freedom of movement of wheel 1452, powered by MLTU 1460.Rotational power is provided at 1460A. Wheel 1452 is shown in its higherposition 1450A on the left side and in its lower position 1450B on theright side. The vertical displacement of wheel 1452, 1451B is enableddue to freedom of movement between power input 1460A and the axis ofwheel 1452. As depicted in FIG. 14B, power input 1460A remains at thesame level 1451A when wheel 1452 moves vertically. In some embodiments,MLTU 1403 or 1460 may be embodied similarly, for example, to MLAG 900,MLAG 1100 or MLAG 1200 of FIGS. 9A-9B, 11, 12, respectively, orcombinations of MLAG 900, MLAG 1100 or MLAG 1200.

Transmission gears of the types that are described above may respond totorque/moment that is transferred through them by developing countertorque acting around the power input axis. It can be desired to restrainand/or eliminate such counter torques because, for example, unrestrainedtorques can affect dynamic behavior of a wheel. For example,unrestrained torques may cause reduced or increased traction of thewheel with the road. This may, for example, affect operation of a brakesystem and/or a steering system of the wheel. In another example, when atransmission gear has two or more gear wheels arranged as describedabove and has the output shaft remote from the input shaft, the entiregearbox can rotate about the input shaft when rotational power istransferred through the gearbox in a rotational direction opposite tothe rotational direction of the input power. This may cause a reduced orincreased traction of the wheel with the road.

In the description below, T_(in) is input torque to a transmission boxat an input shaft (e.g., a shaft of an input gear), and T_(react-out) isa reaction torque at a last gear of the transmission box, andT_(fixture) is a torque at a point of fixture of the transmission box toa reference system (e.g., the ground or a vehicle chassis). According toNewton's laws of motion, conducting a summation of moments about a pointin the system (the system can be defined as the transmission box as awhole) can result in a total of zero (ΣM=0) to reduce counter torques onthe transmission box. The description below provides an example oftorque calculations for a transmission having an odd number of gearswith a transmission ratio of 1:n:

Defining T_(in) is CCW, for odd number of gears, T_(react-out) will beCW.

Because the transmission ratio is 1:n, [T_(in)|=n·T_(react-out)|

When summing moments around the fixture, one gets:

ΣM=T _(in) −T _(react-out) +T _(fixture)=0

Further developing, one can find that T_(fixture)=(1−n)·T_(in)

For a case with 1:1 transmission ratio, T_(fixture)=0

Reference is made now to FIG. 15A, which is a schematic illustration oftransmission box 1530, according to some embodiments of the presentinvention. Transmission box (TB) 1530 includes 3 gears, 1530A meshedwith gears 1530B and gears 1530B meshed with gears 1530C. Transmissionbox (TB) 1530 may be pivotally attached to a reference frame viastationary point 1532. When torque T_(IN) is provided to input gearwheel 1530A, output gear 1530C transfers torque T_(OUT). The totaltorque T_(TOTAL) that TB 1530 experiences may be presented as:T_(TOTAL)=T_(IN)−T_(OUT). In some embodiments, when the transmissionratio is 1:1, T_(IN)=T_(OUT), T_(TOTAL)=0. TB 1530, which includes threegear wheels in a row, can be adapted to transfer rotational power froman input gear wheel to the output gear while the transmission box itselfcan experience virtually no torque (or negligible torque) with respectto the reference frame.

In various embodiments, one or more vibration sensors are placed inpredetermined locations in or on the outer face of the transmission, forsensing and transmitting signals reflecting vibrations of thetransmission. The predetermined locations can be based on pre-acquiredprofiles of similar transmissions may assist in obtaining early warningof required maintenance operation. When one or more signals form the oneor more vibration sensors represent vibration that go out of a rangethat is considered ‘healthy operation’ range, either exceedingmagnitude, frequency and/or temperature, the sensor signals may beprocessed in order to deduce whether or not immediate or closemaintenance is required.

In some embodiments, gears and transmissions as described above mayfurther include a lubrication system, heat dissipation system,mechanical connection(s) and/or reinforcement means, as may be requiredand dictated by the specific intended use.

In various embodiments, one or more rotational speed control means, suchas speed reduction/increasing gears, and/or multi-ratio gears areintegrated with one or more MLTUs, to, for example, provide a rotationalpower transmission solution with a multi-speed with freedom of movementbetween input and output axes.

Transmission gears of the types that are described above may respond totorque/moment that is transferred through them by developing countertorque acting around the power input axis. There can be a need torestrain and/or eliminate such counter torques. For example, when atransmission gear has two or more gear wheels arranged as describedabove and has the output shaft remote from the input shaft, the entiregearbox can rotate about the input shaft when rotational power istransferred through the gearbox in a rotational direction opposite tothe rotational direction of the input power. This may interfere with thedesired way of operation of the powered device.

In some embodiments, MGWT 1530 includes three gear wheels 1530A, 1530Band 1530C. Torque may be provided to the shaft of gear 1530A and may betransferred out via the shaft of gear wheel 1530C. The torque from gear1530A is transferred to gear 1530C via gear wheel 1530B. Torques thatcan be operative when rotational power is provided to the shaft of wheel1530A are: T_(IN) is the torque that gear 1530A provides to gear wheel1530B; T_(OUT) is the torque that gear wheel 1530B provides to theoutput shaft of MGWT 1630; and T_(TOTAL) is the response torque of MGWT1530 when it transfers torque from its input shaft to its output shaft.The magnitude of T_(TOTAL) is the algebraic sum of T_(IN) and T_(OUT).As is evident, when torque is transferred through MGWT 1530 thefollowing yields:

T _(TOTAL) =T _(IN) −T _(OUT)=0 when T _(IN) =T _(OUT), e.g., fortransmission ratio of 1:1.

Reference is now made to FIG. 15B, which is a schematic illustration ofa Multi-gear-wheel transmission (MGWT) 1550, according to someembodiments of the present invention. MGWT 1550 includes three gearwheels 1550A, 1530B and 1550C. Torque may be provided to the shaft ofgear wheel 1550A and may be transferred out via the shaft of gear wheel1550C. The torque from gear wheel 1550A is transferred to gear wheel1550C via gear wheel 1550B. The torque calculation of MGWT 1550 hereapplies:

T _(TOTAL) =T _(IN) −T _(OUT)=0 when T _(IN) =T _(OUT), e.g., fortransmission ratio of 1:1.

Reference is now made to FIG. 15C, which is a schematic illustration ofa two-links multi-gear-wheel transmission (MGWT) 1580, according to someembodiments of the invention. FIG. 15C shows an isometric view oftwo-links MGWT 1580.

MGWT 1580 may include a first part MGWT 1580(1) that may receive atorque T_(IN) via a shaft of gear 1580A and transfer torque T_(OUT(1))via a shaft of gear 1580C. MGWT 1580 may include a second part MGWT1580(2) that receives torque T_(OUT(1)) from the shaft of gear 1580C,which is also the shaft of gear 1580A′, the torque input T_(IN(2)) toMGWT 1580(2). In some embodiments, the torques calculations can be asfollows:

T _(TOTAL(1)) =T _(IN) −T _(OUT(1))=0 when transmission ratio(1) is 1:1within link 1580(1)

T _(TOTAL(2)) =T _(IN(2)) −T _(OUT)=0 when transmission ratio(2) is 1:1within link 1580(2)

Hence:

T _(TOTAL) =T _(TOTAL(1)) +T _(TOTAL(2))=0 when transmission ratios (1)and (2) are 1:1 which is a desired result.

Reference is now made to FIGS. 16A and 16B, which are schematic 3Ddiagrams of a wheel suspension and transmission gear assembly 1600,according to some embodiments of the invention.

Reference is also made to FIG. 16C, which is a schematic 3D diagrams ofa wheel suspension and transmission gear assembly 1600 and a wheel 20assembled to wheel suspension and transmission gear assembly 1600,according to some embodiments of the invention.

According to some embodiments of the invention, wheel suspension andtransmission gear assembly 1600 includes a main arm 1610, a firstlinkage unit 1620 and a second linkage unit 1630.

Main arm 1610 may be pivotally connectable at a connection point 1611 toa shaft point of a wheel. First linkage unit 1620 may be pivotallyconnected at its first end 1621 to main arm 1610.

Second linkage unit 1630 may be pivotally connected at its first end1631 to main arm 1610. In some embodiments, second linkage unit 1630 ispivotally connected at its first end 1631 to main arm 1610 such that atleast a portion of main arm 1610 is between first linkage unit 1620 thesecond linkage unit 1630. In some embodiments, second linkage unit 1630is pivotally connected at its first end 1631 to main arm 1610 such thata second end 1622 of first linkage unit 1620 and a second end 1632 ofsecond linkage unit 1630 are at opposing sides of main arm 1610 withrespect to each other. In some embodiments, second linkage unit 1630 ispivotally connected at its first end 1631 to main arm 1610 such thatmain arm 1610, first linkage unit 1620 and second linkage unit 1630 forma substantially “Z” shape.

In some embodiments, second end 1622 of first linkage unit 1620 ispivotally connectable to the reference frame (e.g., the vehiclechassis). In some embodiments, second end 1632 of second linkage unit1630 is pivotally connectable to the reference frame (e.g., the vehiclechassis).

In some embodiments, main arm 1610, first linkage unit 1620 and secondlinkage unit 1630 are rotatable in planes that are parallel (orsubstantially parallel) to a plane in which a wheel rotates when thewheel is assembled to wheel suspension and transmission gear assembly1600.

In some embodiments, connection point 1611 of main arm 1610 to the shaftpoint of the wheel moves along a straight line in response to a changein a position of at least one of: main arm 1610, first linkage unit 1620and second linkage unit 1630 (e.g., as described hereinabove).

In some embodiments, first linkage unit 1620 and second linkage unit1630 are accommodated within a rim of the wheel when the wheel isassembled to wheel suspension and transmission gear assembly 1600 (e.g.,as shown in FIG. 16C). In some embodiments, first linkage unit 1620 andsecond linkage unit 1630 are fully accommodated within a rim of thewheel when the wheel is assembled to wheel suspension and transmissiongear assembly 1600.

In some embodiments, main arm 1610 includes a first gear 1613 and asecond gear 1614 pivotally connected to main arm 1610 and interconnectedto transmit rotational motion between each other (e.g., as shown in FIG.16B). For example, gears 1613, 1614 of main arm 1610 may be positionedwithin main arm 1610. Main arm 1610 is shown as transparent in FIG. 16Bfor sake of clarity. In some embodiments, one of first linkage unit 1620and second linkage unit 1630 includes a first gear and a second gearpivotally connected thereto and interconnected to transmit rotationalmotion between each other. For example, first linkage unit 1620 includesa first gear 1623 and a second gear 1624 connected to first linkage unit1620 and interconnected to transmit rotational motion between each other(e.g., as shown in FIG. 16B). For example, gears 1623, 1624 of firstlinkage unit 1620 may be positioned within first linkage unit 1620(e.g., as shown in FIG. 16B). Main arm 1610 is shown as transparent inFIG. 16B for sake of clarity. For simplicity, only first linkage unit1620 is being described herein as having two or more gears. However, itis to be understood that in some embodiments second linkage unit 1630(and not first linkage unit 1620) may include two or more gearspivotally connected thereto and interconnected to transmit rotationalmotion between each other.

In some embodiments, gears 1613, 1614 of main arm 1610 rotate in oneplane, and gears 1623, 1624 of first linkage unit 1620 rotate in adifferent plane that is parallel (or substantially parallel) to theplane in which gears 1613, 1614 of main arm 1610 rotate (e.g., as shownin FIG. 16B). In some embodiments, gears 1613, 1614 of main arm 1610 andgears 1623, 1624 of first linkage unit 1620 are rotatable in planes thatare parallel (or substantially parallel) to a plane in which a wheelrotates when the wheel is assembled to wheel suspension and transmissiongear assembly 1600.

In some embodiments, first gear 1613 and second gear 1614 of main arm1610 are rotatable in the same direction. In some embodiments, firstgear 1623 and second gear 1624 of first linkage unit 1620 are rotatablein the same direction.

In some embodiments, main arm 1610 includes an odd number of meshedgears to transmit rotation of first gear 1613 of main arm 1610 to secondgear 1614 of main arm 1610. For example, main arm 1610 may include athird gear 1615 meshed with first gear 1613 and second gear 1614 of mainarm 1610 to transmit rotation of first gear 1613 of main arm 1610 tosecond gear 1614 of main arm 1610 (e.g., as shown in FIG. 16B).

In some embodiments, first linkage unit 1620 includes an odd number ofmeshed gears to transmit rotation of first gear 1623 of first linkageunit 1620 to second gear 1624 of first linkage unit 1620. For example,first linkage unit 1620 may include a third gear 1625 meshed with firstgear 1623 and second gear 1624 of first linkage unit 1620 to transmitrotation of first gear 1623 of first linkage unit 1620 to second gear1624 of first linkage unit 1620 (e.g., as shown in FIG. 16B).

In various embodiments, main arm 1610 includes a drive belt or a drivechain interconnecting first gear 1613 and second gear 1614 of main arm1610 (e.g., instead of third gear 1615, for example as described abovewith respect to FIGS. 11 and 12). In various embodiments, first linkageunit 1620 includes a drive belt or a drive chain interconnecting firstgear 1623 and second gear 1624 of first linkage unit 1620 (e.g., insteadof third gear 1625, for example as described above with respect to FIGS.11 and 12).

In some embodiments, first gear 1613 of main arm 1610 is rotatable bysecond gear 1624 of first linkage unit 1620. In some embodiments, secondgear 1624 of first linkage unit 1620 and first gear 1613 of main arm1610 rotate together about a common rotation axis 1608 (e.g., as shownin FIG. 16B). In some embodiments, common rotation axis 1608 is also theaxis of rotation of first linkage unit 1620 with respect to main arm1610 (e.g., as shown in FIG. 16B).

In some embodiments, first gear 1623 of first linkage unit 1620 iscouplable to an input shaft 30 being powered by a rotational powersource. In some embodiments, second gear 1614 of main arm 1610 iscouplable to an output shaft 32 being coupled to the shaft point of thewheel (e.g., as shown in FIG. 16B).

Since (i) gears 1613, 1614 of main arm 1610 and (ii) gears 1623, 1624 offirst linkage unit 1620 rotate together, when first gear 1623 of firstlinkage unit 1620 is powered via input shaft 10 it causes gear 1623-1625and gears 1613-1615 to rotate with it, each about its respective axis,while each of main arm 1610 and first linkage unit 1620 may remainstationary or move independently. In this manner, rotations of inputshaft 12 may be transmitted via the gears of first linkage unit 1620 andthe gears of main arm 1610 to output shaft 12 and to the shaft point ofthe wheel without interfering (or substantially without interfering)with a suspension motion of main arm 1610 and first linkage unit 1620.

In some embodiments, wheel suspension and transmission gear assembly1600 includes a shock absorbing unit (e.g., similar to shock absorbingunit 140 described above with respect to FIGS. 3A-3B). In someembodiments, the shock absorbing unit is connected to at least one offirst linkage unit 1620 and second linkage unit 1630 to cause the shockabsorbing unit to alter its length in response to a change in a positionof at least one of: main arm 1610, first linkage unit 1620 and secondlinkage unit 1630 (e.g., as described above with respect to FIGS.3A-3B).

Reference is now made to FIG. 16D which is a schematic illustration andto FIG. 16E which is a schematic 3D diagram of a wheel suspension andtransmission gear assembly 1601 and a wheel 20 assembled to wheelsuspension and transmission gear assembly 1601, according to someembodiments of the invention.

In some embodiments, first linkage 1620 of wheel suspension andtransmission gear assembly 1601 is positioned external to a rim 22 ofwheel 20 when wheel 20 is assembled to wheel suspension and transmissiongear assembly 1601 (e.g., as shown in FIGS. 16D and 16E). For example,first linkage 1620 may extend diametrically outside rim 22. For example,first linkage 1620 may laterally extend outside rim 22 toward thereference frame of the vehicle.

In some embodiments, second linkage 1630 of wheel suspension andtransmission gear assembly 1601 is positioned external to rim 22 ofwheel 20 when wheel 20 is assembled to wheel suspension and transmissiongear assembly 1601 (e.g., as shown in FIGS. 16D and 16E). For example,second linkage 1630 may extend diametrically outside rim 22. Forexample, second linkage 1630 may laterally extend outside rim 22 towardthe reference frame of the vehicle.

In some embodiments, both first linkage 1620 and second linkage 1630 ofwheel suspension and transmission gear assembly 1601 are positionedexternal to rim 22 of wheel 20 when wheel 20 is assembled to wheelsuspension and transmission gear assembly 1601.

Reference is now made to FIG. 17, which a schematic 3D diagram of awheel corner module 1700, according to some embodiments of theinvention.

According to some embodiments of the invention, wheel corner module 1700includes a sub-frame 1710, wheel suspension and transmission gearassembly 1720, and a drivetrain unit 1730.

Sub-frame 1705 may be a structural element that may connect at leastsome components of wheel corner module 1700 to a reference frame (e.g.,vehicle's chassis).

Wheel suspension and transmission gear assembly 1720 may be, forexample, similar to wheel suspension and transmission gear assembly 1600described above with respect to FIGS. 16A-16B.

Drivetrain unit 1730 may include an input shaft 1732 coupled to a firstgear of a first linkage unit of wheel suspension and transmission gearassembly 1720 (e.g., first gear 1623 of first linkage unit 1620 asdescribed above with respect to FIGS. 16A-16B). Drivetrain unit 1730 mayinclude an output shaft 1732 coupled to a second gear of a main arm ofwheel suspension and transmission gear assembly 1720 (e.g., second gear1614 of main arm 1610 as described above with respect to FIGS. 16A-16B)and couplable to a shaft point of a wheel (e.g., when the wheel isassembled to wheel corner module 1700). Drivetrain unit 1730 may includea rotational power source 1736 coupled to input shaft 1732.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents will now occur to those of ordinary skill in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

1. A wheel suspension and transmission gear assembly, comprising: a mainarm pivotally connectable at a connection point of the main arm to ashaft point of a wheel; a first linkage unit pivotally connected at itsfirst end to the main arm; and a second linkage unit pivotally connectedat its first end to the main arm such that at least a portion of themain arm is between the first linkage unit and the second linkage unitand such that a second end of the first linkage unit and a second end ofthe second linkage unit are at opposing sides of the main arm withrespect to each other; wherein (i) the main arm and (ii) the firstlinkage unit or the second linkage unit each comprises: a first gear anda second gear pivotally connected thereto and interconnected to transmitrotational motion between each other.
 2. The assembly of claim 1,wherein: the first gear of the first linkage unit or the second linkageunit is couplable to an input shaft being powered by a rotational powersource, the first gear of the main arm is rotatable by the second gearof the first linkage unit or the second linkage unit, and the secondgear of the main arm is couplable to an output shaft being coupled tothe shaft point of the wheel.
 3. The assembly of claim 2, wherein thesecond gear of the first linkage unit or the second linkage unit and thefirst gear of the main arm rotate together about a common axis.
 4. Theassembly of claim 1, wherein the gears of the main arm rotate in oneplane, and the gears of the first linkage unit or the second linkageunit rotate in a different plane that is substantially parallel to theplane in which the gears of the main arm rotate.
 5. The transmissiongear of claim 1, wherein the first gear and the second gear of at leastone of (i) the main arm and (ii) the first linkage unit or the secondlinkage unit, rotate in the same direction.
 6. The assembly of claim 1,wherein at least one of (i) the main arm and (ii) the first linkage unitor the second linkage unit comprises a drive belt or a drive chaininterconnecting the respective first gear and the second gear.
 7. Thetransmission gear of claim 1, wherein at least one of (i) the main armand (ii) the first linkage unit or the second linkage unit comprises anodd number of meshed gears to transmit rotation of the respective firstgear to the respective second gear.
 8. The assembly of claim 1, furthercomprising a shock absorbing unit.
 9. The assembly of claim 8, whereinthe shock absorbing unit is connected to at least one of the firstlinkage unit and the second linkage unit to cause the shock absorbingunit to alter its length in response to a change in a position of atleast one of: the main arm, the first linkage unit and the secondlinkage unit.
 10. The assembly of claim 1, wherein the connection pointof the main arm to the shaft point moves along a straight line inresponse to a change in a position of at least one of: the main arm, thefirst linkage unit and the second linkage unit.
 11. A wheel cornermodule comprising: a wheel suspension and transmission gear assembly,comprising: a main arm pivotally connectable at a connection point ofthe main arm to a shaft point of a wheel; a first linkage unit pivotallyconnected at its first end to the main arm; and a second linkage unitpivotally connected at its first end to the main arm such that at leasta portion of the main arm is between the first linkage unit and thesecond linkage unit and such that a second end of the first linkage unitand a second end of the second linkage unit are at opposing sides of themain arm with respect to each other; wherein (i) the main arm and (ii)the first linkage unit or the second linkage unit each comprises: afirst gear and a second gear pivotally connected thereto andinterconnected to transmit rotational motion between each other; and adrivetrain unit comprising: an input shaft coupled to the first gear ofthe first linkage unit or the second linkage unit; an output shaftcoupled to the second gear of the main arm and couplable to the shaftpoint of the wheel; and a rotational power source coupled to the inputshaft.
 12. The assembly of claim 11, wherein the first gear of the mainarm is rotatable by the second gear of the first linkage unit or thesecond linkage unit.
 13. The assembly of claim 12, wherein the secondgear of the first linkage unit or the second linkage unit and the firstgear of the main arm rotate together about a common axis.
 14. Theassembly of claim 11, wherein the gears of the main arm rotate in oneplane, and the gears of the first linkage unit or the second linkageunit rotate in a different plane that is substantially parallel to theplane in which the gears of the main arm rotate.
 15. The transmissiongear of claim 11, wherein the first gear and the second gear of at leastone of (i) the main arm and (ii) the first linkage unit or the secondlinkage unit, rotate in the same direction.
 16. The assembly of claim11, wherein at least one of (i) the main arm and (ii) the first linkageunit or the second linkage unit comprises a drive belt or a drive chaininterconnecting the respective first gear and the second gear.
 17. Theassembly of claim 11, wherein at least one of (i) the main arm and (ii)the first linkage unit or the second linkage unit comprises an oddnumber of meshed gears to transmit rotation of the respective first gearto the respective second gear.
 18. The assembly of claim 11, furthercomprising a shock absorbing unit.
 19. The assembly of claim 11, whereinthe shock absorbing unit is connected to at least one of the firstlinkage unit and the second linkage unit to cause the shock absorbingunit to alter its length in response to a change in a position of atleast one of: the main arm, the first linkage unit and the secondlinkage unit.
 20. The assembly of claim 11, wherein the connection pointof the main arm to the shaft point moves along a straight line inresponse to a change in a position of at least one of: the main arm, thefirst linkage unit and the second linkage unit.